Magnetoresistance sensor with reduced side reading

Abstract

A magnetoresistance sensor includes a substrate and a sensor structure deposited upon the substrate and having a first lateral side and a second lateral side. The sensor structure includes a layered transverse biasing structure, a free layer deposited upon the layered transverse biasing structure, and a cap layer deposited upon a central portion of the free layer but not upon a side portion of the free layer adjacent to each lateral side. Longitudinal hard biasing structures are disposed laterally adjacent to the lateral sides of the sensor structure. Each longitudinal hard biasing structure has a magnetic seed layer deposited upon the substrate, the respective lateral side of the sensor structure, and the respective side portion of the free layer. A magnetic hard bias layer is deposited upon the seed layer.

What is claimed is:  
     
       1. A magnetoresistance sensor comprising: 
       a substrate;  
       a sensor structure overlying the substrate and having a lateral side, the sensor structure comprising;  
       a layered transverse biasing structure; and  
       a free layer contacting the layered transverse biasing structure, the free layering having;  
       a central portion that is magnetically free to respond to an external magnetic field; and  
       a side portion extending toward the central portion from the lateral side and which is magnetically pinned so that it is not free to respond to the external magnetic field; and  
       a longitudinal hard biasing structure contacting at least the lateral side of the sensor structure; and  
       wherein the side portion of the free layer has a width exceeding about 0.05 micrometers.  
     
     
       2. A magnetoresistance sensor comprising: 
       a substrate;  
       a sensor structure overlying the substrate and having a lateral side, the sensor structure comprising;  
       a layered transverse biasing structure; and  
       a free layer contacting the layered transverse biasing structure, the free layering having;  
       a central portion that is magnetically free to respond to an external magnetic field; and  
       a side portion extending toward the central portion from the lateral side and which is magnetically pinned so that it is not free to respond to the external magnetic field; and  
       a longitudinal hard biasing structure contacting at least the lateral side of the sensor structure, wherein the longitudinal hard biasing structure comprises a seed layer contacting the substrate, the lateral side of the sensor structure, and the side portion of the free layer, the seed layer having a seed layer crystal structure and being a magnetic material, and a magnetic hard bias layer contacting the seed layer, the hard bias layer having a hard bias layer crystal structure.  
     
     
       3. The magnetoresistance sensor of  claim 2 , wherein the seed layer crystal structure is body centered cubic, and the hard bias layer crystal structure is hexagonal close packed. 
     
     
       4. The magnetoresistance sensor of  claim 2 , wherein the sensor structure comprises a giant magnetoresistance sensor. 
     
     
       5. The magnetoresistance sensor of  claim 2 , wherein the sensor structure further includes a cap layer overlying at least a portion of the free layer. 
     
     
       6. A magnetoresistance sensor comprising: 
       a substrate;  
       a sensor structure deposited upon the substrate and having a first lateral side and a second lateral side, the sensor structure comprising  
       a layered transverse biasing structure,  
       a free layer contacting the layered transverse biasing structure, and  
       a cap layer deposited upon a central portion of the free layer but not upon a side portion of the free layer adjacent to each lateral side thereof; and  
       a first longitudinal hard biaisng structure laterally adjacent to the first lateral side of the sensor structure and a second longitudinal hard biasing structure laterally adjacent to the second lateral side of the sensor structure, each longitudinal hard biasing structure comprising  
       a seed layer deposited upon the substrate, each lateral side of the sensor structure, and each side portion of the free layer, the seed layer having a seed layer crystal structure and being a magnetic material, and  
       a magnetic hard bias layer deposited upon the seed layer, the hard bias layer having a hard bias layer crystal structure.  
     
     
       7. The magnetoresistance sensor of  claim 6 , wherein the side portion of the free layer has a width exceeding about 0.05 micrometers. 
     
     
       8. The magnetoresistance sensor of  claim 6 , wherein the sensor structure comprises a giant magnetoresistance sensor. 
     
     
       9. The magnetoresistance sensor of  claim 6 , therein the hard bias layer physically contacts at least a portion of the cap layer. 
     
     
       10. The magnetoresistance sensor of  claim 6 , wherein the seed layer crystal structure is body centered cubic, and the hard bias layer crystal structure is hexagonal close packed. 
     
     
       11. The magnetoresistance sensor of  claim 6 , wherein the seed layer is a CoFeCr alloy, and the hard bias layer is a CoPtCr alloy.